Morals refine manners, as manners refine morals.

[Die Sittlichkeit verfeinert die Sitte, und die Sitte wiederum die Sittlichkeit.]

Marie von Ebner-Eschenbach (1830-1916) Austrian writer

Aphorisms [Aphorismen], No. 133 (1880) [tr. Wister (1883)]
    (Source)

(Source (German)). Alternate translation:

Morality refines customs and customs in turn refine morality.
[tr. Scrase/Mieder (1994)]